Fused silica capillary interferometer with a layer-by-layer functional coating for the analysis of chemicals content in aqueous solutions

A simple fused silica capillary interferometric (FSCI) sensor has been proposed and investigated for the detection and analysis of multiple chemical compounds content in aqueous solutions. The sensor was fabricated by splicing a commercially available fused silica capillary (FSC) with two single mode fibers to create a 0.7 cm long air cavity. The fiber surface was functionalized with two different polymers: poly (allylamine hydrochloride) (PAH) and sol-gel silica in sequence using a layer-by-layer deposition method. The operating principle of the sensor relies on light interference in the fused silica capillary cavity due to adhesion of the different chemical compounds on the functional coating surface. Studies of the sensors response to the presence of five different compounds in water solutions at different concentrations have been carried out and the results have been analyzed using the principal component analysis (PCA). This work is a preliminary investigation towards the development of a novel method for assessment of content and quality of alcoholic beverages in real time using functionalized FSCIs

Chapter Optical fibers and optical fiber sensors used in radiation monitoring

Communications engineering / telecommunication

Understanding the policies and carbon accounting frameworks which are defining the potential role of biobased products to meet climate change targets

Climate change has become an important challenge at International, European, National and Regional level. Mitigation of climate change by preventing and reducing the emission of greenhouse gases (GHG) into the atmosphere is needed to make the impacts of climate change less severe. To ensure this, different mitigation frameworks have been created. These frameworks set specific GHG reduction goals and provide a more structured approach to solve this problem. This report aims to provide information to the Dutch Ministry of Agriculture, Nature and Food Quality (LNV) on and how some climate change mitigation frameworks are including the increase forestry and agricultural biomass supply to produce chemicals and materials that can contribute to the reduction of GHG emission. This desktop research follows a ‘systems perspective approach’ to study the role of biobased materials’ 1 in the reduction of GHG emission. This approach allows the understanding of interactions between biobased products, national inventories and global agreements. Understanding these links and having knowledge on which GHG gases accounting methods are being applied is necessary for the identification of possible drawbacks and for the development of future policy guidelines. After this review, we conclude that it is important to be familiar with and recognize the value in current existing accounting methodologies. However, existing frameworks are still lacking important features which could enable more robust account methodologies for carbon sequestration and storage in biobased materials. At this moment in time, the European Commission is working on proposals like the ‘Carbon Farming framework’ and ‘carbon removals certification framework’ (December 2022) and introducing a ‘carbon storage products pool’, these proposals could play and important role on establishing clear accounting rules that connect the biomass production to biobased materials and its contribution to support National Policies towards GHG reduction targets. This will require collaboration and information exchange between European countries. Therefore, is important to follow closely the evolution of these frameworks and their proposed accounting rules. This document is organized in the following way: • Section 2, introduces terminologies, frameworks and methods for GHG accounting at different levels International, Europe and Netherlands. • Section 3 is dedicated to understanding how biobased products for could contribute to the Climate targets by substituting other GHG intensive materials, extending the life span of the product or by cascading use of the biomass. • Section 4 shows two examples on how the GHG balances of two different linear biobased supply chains are estimated at the product accounting level and how this relates to the national level inventory reporting and the global agreements. • Section 5 presents our conclusions and recommendations

Chapter Optical fibers and optical fiber sensors used in radiation monitoring

Communications engineering / telecommunication

Water phantom characterization of a novel optical fiber sensor for LDR brachytherapy

This work considers the feasibility of using a novel optical fiber-based sensor, employing a terbium-doped gadolinium oxysulfide (Gd2O2S:Tb) inorganic scintillator, as a real-time in vivo dosimetry solution for applications in low-dose-rate (LDR) prostate brachytherapy (BT). This study specifically considers the influence of scintillator geometry (hemisphere tip versus cylindrical cavity), polymethyl methacrylate (PMMA) fiber core diameter (0.5 versus 1.0 mm), and sensor housing material (stainless steel versus plastic) on the measured scintillation signal. Characterization measurements were performed using a silicon photon-multiplier (SiPM) detector and a commercial water phantom system, integrated with custom 3-D printed components to allow for precise positioning of the LDR BT radiation source with respect to the optical fiber sensor (OFS). Significant differences in the rate of fall-off in the scintillation signal, with distance from the source, were observed between the different scintillator geometries considered. The hemisphere tip geometry was shown to be the most accurate, tracking with the expected fall-off in dose-rate, within measurement uncertainty. Reducing the fiber core diameter from 1.0 to 0.5 mm resulted in a sixfold reduction in the detected scintillation signal. A further 57% reduction was observed when housing the 0.5-mm fiber within a stainless steel LDR BT needle applicator. Initial results demonstrate the feasibility of employing an OFS, for applications in LDR BT, given the excellent agreement of measurements with theoretical expectations. Furthermore, a calibration process has been described for converting the detected scintillation signal into absorbed dose/dose rate, using our water phantom-based experimental setup.</p

Low cost portable 3-D printed optical fiber sensor for real-time monitoring of lower back bending

A mechanically robust and compact novel optical fiber sensor system is described to monitor the bending of the lower back bone in both sagittal and frontal planes. Both bending modes are monitored through the change of the coupled optical intensity ratio between three output fibers aligned to one input fiber. This provides real-time feedback to the clinical therapist when different postures are sustained. The output ratio is calibrated against bending angle using an optical setup utilizing a precise rotational stage. The measured data is also correlated to the curvature of the lower back through the implementation of an ad-hoc imaging scheme. Sequences of images are also captured while the optical fiber sensor is attached on the skin surface to the lower back. The imaging system tracks three spots placed on the sensor and skin to trace the angle changes. The optical fiber sensor system has an operational range between −12° to +12°. It is demonstrated that the sensor is suitable for clinical use with the additional benefits of being non-invasive, robust, straightforward to use and low cost. It also allows record of spinal curvature in the home and other real-world settings and potentially reduces the requirement for the use of X-rays and MRI in the clinic

PAS-WRAP: A new approach to photoacoustic sensing, a new opportunity for the optical fiber sensor community

We present a new approach to optical fiber photoacoustic spectroscopy for gas trace detection. After an explanation of its working principle, we show the results of the measurements obtained with our first prototype. We then analyze the advantages that this approach may provide, and further discuss how the expertise developed by the optical fiber sensor community may contribute to the field of photoacoustic gas sensing

Compact and low-cost optical fiber respiratory monitoring sensor based on intensity interrogation

In this paper, a plastic optical fiber sensor for respiratory monitoring purposes is presented. The sensor was integrated into a small, robust, and flexible package to be attached directly on a wide variety of positions on the upper body tomonitor themotion induced by breathing. The sensor's operating principle is based on the variation in the intensity of the optical coupling intensity ratio between an input and a set of aligned output optical fibers. The system is demonstrated to be able to track the time-varying breathing signal when the sensor is placed at four different positions of the torso (including diaphragmatic and upper costal). The accuracy of the device is confirmed by a simultaneous comparison of the results with a commercial respiratory monitoring device. Measurement of breathing rate on four different healthy subjects showed excellent agreement with the measurement from the commercial respiratory monitoring device. The proposed fiber optic respiration sensor provides the advantages of being relatively low cost, compact, and simple in construction compared to the conventional existing respiration sensors